Standardising website carbon calculations on Earth Day 2022

Written by Tom Greenwood - April 22, 2022

It’s been many years now since our team here at Wholegrain Digital developed the first methodology for calculating the carbon emissions of websites and later launched our free website carbon calculator to the public.

Since then we’ve learned a huge amount about how to create more energy efficient and low carbon web services, radically transforming our own design and development processes as a result. We’ve also started to offer new services, consulting on digital sustainability to organisations looking to improve their environmental performance.

Our carbon calculation tool at has completed several million tests and we’ve had two versions of the formula behind it, each being updated with newer data as it became available. Now we’re launching the third version, today on Earth Day 2022. Our v3 formula went live this week and it’s not just more up to date in terms of the research behind it, but this launch represents a step towards standardisation in our industry.

When we first launched it stood on its own as a tool for calculating the energy and carbon emissions of websites, but over the past few years, a growing number of imitations have sprung up, either using variations of our v1 or v2 formulas or implementing new methodologies without publishing them transparently. There is also growing demand from providers of other tools wanting to integrate energy and carbon metrics and needing a standardised approach that they can rely on. The proliferation of variations has started to become confusing and increasingly opens up the risk of green washing in our industry.

For version 3, we therefore decided to partner with industry leaders to collaborate on a standardised public methodology. Our partners in this project have been US based green web pioneers Mightybytes, environmental consultant Rym Baouendi, web performance and environmental app EcoPing and The Green Web Foundation.

The updated methodology is published on the Sustainable Web Design website and future updates will be published there. It is now live on, the new version of Ecograder (the pioneering tool from Mightybytes), EcoPing, and is provided in a handy piece of code from The Green Web Foundation, CO2.js.

Keeping something like this up to date requires a huge amount of time and effort, analysing new research papers and comparing methodologies. This collaboration has not only made the project more technically robust but also more sustainable from a time and resource perspective. We will continue to update this with our partners moving forward. We hope that many others will embrace our open approach and join us in creating some standardisation across the industry.

Moving forward, we plan to continue this collaboration to standardise best practices, not just in website carbon emission and energy calculations, but also in approaches to environmentally responsible web design more broadly. If you’re interested in getting involved in that collaboration, please join check out this post on the W3C Sustainable Web Community Group